Detergent compositions containing novel crystalline forms of optical brighteners

ABSTRACT

Novel crystalline needle forms of the fluorescent compounds disodium 4,4&#39;-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2&#39;-stilbenedisulfonate and disodium 4,4&#39;-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2&#39;-stilbenedisulfonate, useful as optical brightening agents, particularly when incorporated into detergent compositions. The novel crystalline forms are prepared by heating the compound in an aqueous alkaline medium containing excess amine reactant.

This application is a continuation-in-part of our prior copendingapplication Ser. No. 834,560 now U.S. Pat. No. 3,951,960, filed June 18,1969, which in turn is a continuation-in-part of our now-abandonedapplication Ser. No. 283,558, filed May 27, 1963 and of our nowabandoned application Ser. No. 526,351, filed Feb. 10, 1966, whichlatter application was a continuation-in-part of our now abandonedapplication Ser. No. 177,743, filed Mar. 6, 1962.

BACKGROUND OF THE INVENTION

a. Field of the Invention

This invention relates to salts of the fluorescent compounds4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonicacid and4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonic inacid novel crystalline forms having improved properties as opticalbleaching agents, to new articles of manufacture containing said saltsin the novel forms, to detergent compositions containing said salts inthe novel forms, and to the preparation of same.

B. Description of the Prior Art

Disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate(Formula I) ##STR1## and disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate(Formula II) ##STR2## are known compounds which have valuable propertiesas fluorescent optical bleaching agents in detergent compositions forthe laundering of textile goods. The dianilino-,dimorpholino-substituted compound of Formula I, its preparation andutility as an optical bleach have been described, for example, in U.S.Pat. No. 2,612,501, patented Sept. 30, 1952. Similarly, thetetra-anilino-substituted compound of Formula II, its preparation andutility as an optical whitening and brightening agent have beendescribed in the prior art, for example, in Japanese Pat. No. 3988/51,issued July 24, 1951, and in German Auslegeschrift 1,100,583, issuedMar. 2, 1961. The prior art teaches that these compounds are ordinarilyprepared in the following manner. One molecular proportion of disodium4,4'-diaminostilbene-2,2'-disulfonate is condensed with two molecularproportions of cyanuric chloride at low temperature (0-5° C); then, inthe case of the compound of Formula I, one molecular proportion of theresulting disodium4,4'-bis(4,6-dichloro-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate isaminated with two molecular proportions of aniline or morpholine atapproximately 50° C; and one molecular proportion of the resultingproduct, that is, disodium,4,4'-bis(4-chloro-6-anilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateor disodium4,4'-bis(4-chloro-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateis aminated at 95°-100° C with two molecular proportions of eithermorpholine or aniline, respectively, to produce disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate.In the case of the compound of Formula II, the intermediate disodium4,4'-bis(4,6-dichloro-s-triazin-2-ylamino)-2,2'-disulfonate isinteracted with aniline at a somewhat higher temperature (usually in therange 30°-100° C) to replace the four chloro substituents with fouraniline groups. In each of these steps, sufficient alkali is added tothe reaction mixture to keep it substantially neutral during thereaction.

As produced by this known method of manufacture, the disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateis a pale yellow amorphous (non-crystalline) solid. This amorphousproduct has the drawback of being light-sensitive, changing from yellowto green to brown during relatively short exposures to light, forinstance, one to two hours. The light sensitivity is objectionable,especially when the product is to be incorporated into white detergents.As produced by the known method of manufacture, disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate isa yellow solid which is usually marketed and used in the light-sensitiveamorphous form in which it is initially obtained by the above method or,in some instances, the amorphous form has been converted into a yellowcrystalline form consisting predominantly of a plate-like crystallineform. Furthermore, German Auslegeschrift 1,100,583 discloses a methodfor producing the compound in the form of a mixture of plates andcrystalline rods or needles which is yellow and undesirable for themanufacture of detergent compositions. When any of these forms of theproduct is incorporated into detergent compositions, it has the drawbackof poor resistance to chemical attack by the hypochlorite bleachcommonly added during laundering, so that a substantial proportion ofthe whitening and brightening effect is destroyed. Moreover, in manyinstances, it has been found that they impart an undesirable yellow castto white solid detergent compositions.

SUMMARY OF THE INVENTION

In one of its composition aspects, this invention resides in a compoundselected from the group consisting of di-sodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatein the form of cyrstalline needles and disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate inimproved crystalline needle forms characterized by their X-raydiffraction data and indices of refraction. In another of itscomposition aspects, the invention resides in a soap or detergentcomposition having incorporated therein an effective brightening amountof a compound selected from the group consisting of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateand disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate inthe form of said novel crystalline needles. In one of its processaspects, this invention resides in the method which comprises heating,at a temperature in the approximate range 90°-200° C, amorphous disodium4,4'-bis-4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatewith one-half to five molecular proportions of aniline or morpholine inan aqueous medium having an initial pH in the range of 8 to 12 untilapproximately 80 to 100 percent of the disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateis in the form of crystalline needles. In another of its processaspects, the invention resides in the method which comprises heating, ata temperature in the approximate range 90°-200° C, an amorphous or plateform of disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatewith from one to five molecular proportions of aniline in an aqueousmedium having an initial pH in the approximate range 8 to 12 untilapproximately 80 to 100 percent of the disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate isin the form of birefringent crystalline rods.

DETAILED DESCRIPTION INCLUSIVE OF THE PREFERRED EMBODIMENTS

It is a particular object of the instant invention to increase theeffectiveness and value of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateand disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate aswhitening and brightening agents, by providing the said compounds in anovel and improved crystalline form in which the drawbacks pointed outabove are minimized.

In accordance with the instant invention, we produce disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateand disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateeither largely or wholly, as desired, in the form of white to lightcream colored needle-shaped crystals which can be readily distinguishedqualitatively from the old amorphous form either by simple visualexamination under a microscope or by determination of the characteristicX-ray diffraction powder pattern. The art of crystallography generallyrefers to crystals in this novel form either as needles or rods, and thetwo terms, being equivalent, are used interchangeably. The novelcrystalline rod or needle form of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateshows excellent light stability, its color being virtually unaffected bythe same exposures to ultraviolet light which produces an easilydiscernible discoloration of the amorphous forms.

When viewed with a polarizing microscope equipped with crossed Nicolprisms, the amorphous forms of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateappear as agglomerates of powder which transmit no light. X-raydiffraction pictures, obtained by the powder method using nickelfiltered copper K.sub.α radiation, show for the amorphous forms of thecompound only a diffuse grey pattern, as is characteristic of associatedmolecules lacking an ordered state, whereas the new crystalline needleform shows characteristic diffraction patterns.

Like the amorphous forms, the crystalline needle forms of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateand disodium4,4'-bis-(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate donot melt when heated at high tempertures, for example, up to 300° C.

DISODIUM4,4'-BIS(4-ANILINO-6-MORPHOLINO-S-TRIAZIN-2-YLAMINO)-2,2'-STILBENEDISULFONATE

The solutions of the needle form and the amorphous form of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateare not distinguishable from each other on the basis of ultravioletabsorption curves. When the solids are viewed under ultraviolet light,the amorphous form as commercially produced has a dull greenish-yellowcolor, and the needle form has a bluish-white color.

The needle form of the compound, however, shows a characteristicdiffraction pattern with the following interplanar spacings, obtained bythe powder method using nickel-filtered copper K.sub.α radiation:

    ______________________________________                                        INTERPLANAR SPACINGS, A.                                                      26.75                                                                         10.04                                                                         9.20                                                                          8.42                                                                          6.02                                                                          5.34                                                                          5.18                                                                          4.79                                                                          4.35                                                                          4.29                                                                          ______________________________________                                    

In accordance with our invention, the production of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatein the form of crystalline needles can be accomplished by employing asthe starting material the conventional amorphous form which is theproduct obtained by using the known procedure, as outline above, forreplacing by amination the four chloro substituents in disodium4,4'-bis(4,6-dichloro-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate withtwo anilino and two morpholino substituents. Advantageously, thestarting amorphous disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateis used directly in the form of the water-wet pulp produced by theamination reactions. Our new method comprises heating, at a temperaturein the approximate range 90°-200° C, amorphous disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatewith approximately one-half to five molecular proportions of an amine ofthe group consisting of aniline and morpholine in an aqueous mediumhaving an initial pH in the approximate range 8 to 12 until all or asubstantial proportion (for instance, 80 percent or more) of thedisodium4,4'-(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateis in the form of crystalline needles. This heating can be carried outunder atmospheric pressure at a temperature in the range fromapproximately 90° C to reflux temperature (about 100° C), or in anautoclave at a temperature up to approximately 200° C. Substantiallycomplete conversion to the crystalline needle form is usually effectedwithin 3 to 4 hours at most, and under optimum conditions is effectedwithin twenty minutes or less. The product is readily recovered from theaqueous suspending medium for instance, by filtration.

When atmospheric pressure is employed in our method, we prefer to mixapproximately two and one-half to five (advantageously, about three tofour) moles of aniline or morpholine (or, if desired, mixture thereof)with each mole of amorphous disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate,the latter as a 5 to 20 percent (advantageously, about 10 percent)slurry in water, adjust the pH of the aqueous medium to approximately8.5-9.5 with sodium hydroxide or a suitable basic sodium salt as anequivalent thereof, and then heat the resulting mixture at refluxtemperature until substantially all of the disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateis in crystalline needle form.

When an autoclave is employed in our new method, we prefer to mixapproximately one-half to three (advantageously, about one) moles ofaniline or morpholine (if desired, mixtures of the two) with each moleof amorphous disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate,the latter as a 5 to 20 percent (advantageously, about 10 percent)slurry in water, adjust the pH of the aqueous medium to approximately10.0-10.5 with sodium hydroxide or a suitable basic sodium salt as anequivalent thereof, and then heat the resulting mixture at 125°-175° Cuntil substantially all of the disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateis in crystalline needle form.

We have found that the presence of inorganic salts such as sodiumchloride in unpurified amorphous starting material slows down theconversion to the crystalline needle form somewhat, and under suchcircumstances, a heating period of about four hours may be required evenwhen the conversion conditions are otherwise optimum. Despite thislengthening of the heating period, which can be readily obviated by useof conventional purification procedures, it is usually more economicalin commercial production to use a slightly impure starting material(that is, wherein the percentage of inorganic salts is no more thanabout 10 percent) as such rather than incur the losses attendant topurification procedures.

In addition to having excellent light-stability, the novel crystallineneedle form of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateafforded by our invention also has improved optical bleachingproperties, as compared with the corresponding known amorphous form,when used in detergent compositions to launder cotton fabrics in thepresence of hypochlorite bleach. Thus, for example, under theseconditions, we found that when the novel needle form of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatewas used the loss of whitening effect due to action of sodiumhypochlorite bleach was only about 80 percent as great as the lossincurred when the amorphous form of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatewas used.

DISODIUM4,4'-BIS(4,6-DIANILINO-S-TRIAZIN-2-YLAMINO)-2,2'-STILBENEDISULFONATE

In accordance with the novel methods of the instant inventionhereinafter described, we produce disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateeither largely or wholly, as desired, in the form of novel rod-shapedcrystals. At least two distinct rod-like crystalline forms (A and B) areproduced according to the processes described herein. The crystallinerod form produced in preponderant quantities is determined by theparticular choice of reaction conditions employed within the range ofconditions described herein.

The novel crystals are small, white, birefringent rods in which thelowest index of refraction is parallel to the long axis of the rod. Inrod form A, this index has a value between 1.53 and 1.54; in the rodform B, the corresponding index has a value between 1.88 and 1.94. Thevalue for the other index (or indices) in each of the rod forms isgreater than 1.70. Since only parallel extinction can be noted in therod forms they belong to either the tetragonal or the orthorhombicsystem.

We have found that crystalline rod form A tends to crystallize in twomodifications: one contains up to about six percent water which appearsto be in the crystalline lattice, and the other is substantiallyanhydrous (containing approximately 0.8 percent water). The indices ofrefraction of the two modifications are the same, thus offering a meansof identification of the crystals as rod form A. However, the X-raydiffraction patterns of the two modifications of rod form A showdistinct differences in the crystalline structure, as set forth morefully below. No other differences in the physical properties of the twomodifications have been observed.

The novel crystalline rod forms of disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateprovided by this invention can be readily distinguished qualitativelyfrom the old crystalline plate form or amorphous form either by simplevisual examination under a microscope or by determination of thecharacteristic X-ray diffraction powder patterns.

The crystalline plate form of disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateappears as elongated, roughly rectangular plates. These crystals have astrong propensity for formation of overgrowths or possibly twinnedcrystals together with lack of visible details of other than the twoprimary faces, so that a study of the crystal geometry is madedifficult.

A quantitative differentiation between the new rod forms and thepreviously known plate form can be made by comparison of interplanarspacings as shown by the X-ray diffraction data, set forth below,obtained in each instance by the powder method using nickel filteredcopper K.sub.α radiation. Moreover, the rod forms are differentiatedfrom one another by their individual characteristic X-ray diffractionpatterns. Rod form A containing water and the substantially anhydrousrod form A have individual X-ray diffraction patterns as shown. Rod formB is characterized by five prominent lines in the diffraction pattern asshown.

    ______________________________________                                        INTERPLANAR SPACINGS, A.                                                      Rod Form A                                                                              Rod Form A                                                          (Hydrated (Anhydrous                                                          form)     form)       Rod Form B  Plate Form                                  ______________________________________                                        6.23      17.6        13.2        6.72                                        5.90      16.6        5.78        6.30                                        5.70      13.6        4.96        5.99                                        5.59      9.50        4.52        5.57                                        5.51      6.80        3.88        5.32                                        5.34      5.53                    5.00                                        4.90      5.33                    4.76                                        4.85      3.96                    4.52                                        4.60                              4.08                                        3.98                              3.88                                        3.82                              3.72                                        3.64                              3.67                                        3.44                              3.61                                        3.28                              3.48                                        3.22                              3.39                                                                          3.26                                                                          3.18                                                                          3.04                                        ______________________________________                                    

The amorphous (non-crystalline) form of disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbendisulfonate isreadily distinguished from the crystalline plate and rod forms byviewing them with a polarizing microscope equipped with crossed Nicolprisms. When so viewed, the amorphous form appears as agglomerates ofpowder which transmit no light. An X-ray diffraction picture of theamorphous form shows only a diffuse grey pattern, as is characteristicof associated molecules lacking an ordered state.

The solutions of the rod, plate, and amorphous forms are notdistinguishable from each other on the basis of ultraviolet absorptioncurves. When the solids are viewed under ultraviolet light, theamorphous and the plate forms have a pale blue color, the latter beingof greater intensity of brightness, and the rod forms each have a violetcolor with low intensity of brightness.

As stated above, German Auslegeschrift 1,100,583 discloses a process ofpreparing disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate andthe product so prepared is characterized as a mixture of plates and rodshaving inferior properties. Furthermore, the X-ray diffraction patternof the product produced in accordance with the German Auslegeschriftprocedure is entirely different from the X-ray diffraction patterns ofour improved forms. Following are the interplanar spacings of theproduct prepared in accordance with the German Auslegeschrift procedure:

    ______________________________________                                        INTERPLANAR SPACINGS, A.                                                      26.36                                                                         17.31                                                                         13.38                                                                          6.75                                                                          5.30                                                                         ______________________________________                                    

In accordance with our invention, the production of disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate ineither of the crystalline rod forms can be accomplished by employing asthe starting material the conventional amorphous form which is theproduct obtained by using any of the published procedures for carryingout the interaction of disodium4,4'-bis(4,6-dichloro-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate withaniline; or alternatively, we can use the crystalline plate form, whichwe have found can be produced by slurrying the amorphous form in amixture of water and acetone, refluxing the slurry for an hour or so,making the mixture barely alkaline to phenolphthalein by adding 50percent aqueous sodium hydroxide solution, refluxing the mixture foranother hour or so, and then filtering the mixture to recover thecrystalline plate form. Our new method of preparing the novel rod formscomprises heating, at a temperature in the approximate range 90°-200° C,the amorphous form or the crystalline plate form of disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate, ora mixture of the amorphous and crystalline plate form, withapproximately one to five molecular proportions of aniline in an aqueousmedium having an initial pH in the approximate range 8 to 12 until allor a substantial proportion (for instance 80 percent or more) of thedisodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino-2,2'-stilbenedisulfonate isin the form of crystalline rods. Substantially complete conversion tocrystalline rod form is usually effected within three to four hours atmost, and under optimum conditions is effected within twenty minutes orless. The product is readily recovered from the aqueous suspendingmedium, for instance by filtration. This heating can be carried outunder atmospheric pressure at a temperature in the range fromapproximately 90° C to reflux temperature (about 100° C), or in anautoclave at a temperature up to approximately 200° C.

When atmospheric pressure is employed in our method, we prefer to mixapproximately two and one-half to five (advantageously, about three tofour) moles of aniline with each mole of amorphous or crystalline plateform of disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate,the latter as a 5 to 20 percent (advantageously, about 10 percent)slurry in water, adjust the pH of the aqueous medium to approximately8.5-9.5, with sodium hydroxide or a suitable basic sodium salt as anequivalent thereof, and then heat the resulting mixture at refluxtemperature until substantially all of the disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate isin crystalline rod form. The crystalline form produced in this way isrod form A.

When an autoclave is employed in our new method, we prefer to mixapproximately one to three (advantageously, about two) moles of anilinewith each mole of amorphous or crystalline plate form of disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate,the latter as a 5 to 20 percent (advantageously, about 10 percent)slurry in water, adjust the pH of the aqueous medium to approximately10.0-10.5 with sodium hydroxide or a suitable basic sodium salt as anequivalent thereof, and then heat the resulting mixture at 135°-175° Cuntil substantially all of the disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate isin crystalline rod form. The crystalline form produced in this manner isrod form B described above.

The relative proportions of rod form A and rod form B produced in theinstant process are dependent primarily upon the reaction temperature.Thus, below 135° C, a preponderance of rod form A is generally produced,and above 135° C, a preponderance of rod form B is produced. However,rod form B can be obtained at lower temperatures, for example, about125° C, by employing a somewhat larger quantity of aniline, for example,from four to five molecular equivalents for each molecular equivalent ofbrightener.

We have found that the presence of inorganic salts such as sodiumchloride in unpurified amorphous or crystalline plate starting materialslows down the conversion to crystalline rod form somewhat, and undersuch circumstances, a heating period of about four hours may be requiredeven when the conversion conditions are otherwise optimum. Despite thislengthening of the heating period, which can be readily obviated by useof conventional purification procedures, it is usually more economicalin commercial production to use a slightly impure starting material(that is, wherein the percentage of inorganic salts is no more thanabout 5 percent) as such rather than incur the losses attendant topurification procedures.

The novel crystalline rod forms of disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateafforded by our invention unexpectedly have substantially improvedoptical bleaching properties, as compared with the correspondingconventional amorphous and crystalline plate forms and the knowncrystalline plate and rod-form mixture. Thus, when the amorphous,crystalline plate, and crystalline rod forms are incorporated intodetergent compositions which are then used in a conventional textilelaundering procedure wherein a hypochlorite bleaching agent is used, wehave found that our novel crystalline rod forms are much more stablethan the old amorphous and crystalline plate forms toward thedestructive action of the hypochlorite bleaching agent. This increasedstability when the novel crystalline rod forms are used results in asignificant increase in the whitening and brightening effect produced onthe textiles. Moreover, the novel crystalline rod forms are not onlyfree of any undesirable yellowing effect on white solid detergentcompositions when incorporated therein at concentration levels ofpractical use but, to the contrary, in many instances they have adesirable whitening effect which improves the appearance of suchdetergent compositions.

Our invention is illustrated by the following examples without, however,being limited thereto.

EXAMPLE 1

A slurry of 9.2 g of yellow amorphous disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate(as an unpurified water-wet pulp obtained by interacting two molecularproportions of morpholine with disodium4,4'-bis(-dichloro-s-triazin--dichloro-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateand then interacting one molecular proportion of the resultant disodium4,4'-bis(4-chloro-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatewith two molecular proportions of aniline), 2.3 g of aniline, 90 ml ofwater, and 5 ml of 1N aqueous sodium hydroxide solution was stirred andheated at reflux temperature (approximately 100° C) for forty-fiveminutes. The mixture was then filtered while hot (about 90°-95° C) andthe solid thus collected was washed with hot (about 80° C) water untilthe washings were neutral to Brilliant Yellow indicator and colorless.The product was dried at 70° C. There was thus obtained 5.2 g ofcrystalline white needles of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate.

EXAMPLE 2

A slurry of 9.2 g of amorphous disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate,2.2 g of morpholine, 90 ml of water, and 5 ml of 1N aqueous sodiumhydroxide solution was stirred and heated at reflux temperature for 45minutes. The mixture was then filtered while hot and the solid thuscollected was washed with hot water until the washings were neutral toBrilliant Yellow indicator and colorless. The product was dried at 70°C. There was thus obtained 4.6 g of cream colored crystalline needles ofdisodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate.

EXAMPLE 3

A slurry of 9.2 g of amorphous disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate,1.15 g of aniline, 1.1 g of morpholine, 90 ml of water, and 5 ml of 1Naqueous sodium hydroxide solution was stirred and heated at refluxtemperature for one and one-quarter hours. The mixture was then filteredwhile hot and the solid thus collected was washed with hot water untilthe washings were neutral to Brilliant Yellow indicator and colorless.The product was dried at 70° C. There was thus obtained 5.5 g of creamcolored crystalline needles of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate.

EXAMPLE 4

A slurry of 74 g of amorphous disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatein 600 ml of water was heated to reflux temperature, and sufficientaqueous sodium hydroxide solution was added to make the mixture alkalineto phenolphthalein. There was then added 7.5 g of aniline, and theresulting mixture was heated at 135° C in an autoclave for 2 hours. Thereaction mixture was allowed to cool to room temperature and was thenfiltered. The solid thus collected was washed with a 15 percent aqueoussolution of sodium chloride. The product was dried at 70° C. There wasthus obtained 70 g of cream to yellow crystalline needles of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate.

EXAMPLE 5

A mixture of 96 g of amorphous disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate(as as unpurified water-wet pulp obtained by interacting two molecularproportions of morpholine with disodium4,4'-bis(4,6-dichloro-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate andthen interacting one molecular proportion of the resultant disodium4,4'-bis(4-chloro-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatewith two molecular proportions of aniline), 30 g of aniline, and 1000 mlof water was made alkaline to phenolphthalein by addition of aqueoussodium hydroxide solution, and the mixture was heated at refluxtemperature (approximately 100° C) for four hours. The reaction mixturewas then filtered while hot and the solid thus collected was washed with500 ml of hot (85° C) 15 percent aqueous sodium chloride solution. Theproduct was dried at 70° C. There was thus obtained 86.5 g of creamcolored crystalline needles of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate.

EXAMPLE 6

A slurry of 8.5 g of yellow amorphous disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate (asan unpurified water-wet pulp obtained by interacting aniline withdisodium 4,4'L-bis(4,6-dichloro-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate) in 2.5g of aniline, 80 ml of water, and 1 ml of 1N aqueous sodium hydroxidesolution was heated at reflux temperture (approximately 100° C). Duringthe reflux period, samples were removed periodically from the mixtureand examined microscopically. After about one hour of refluxing,rod-shaped crystals were detected in a sample of the mixture. Afterabout three and one-half hours of refluxing virtually all of the solidin the mixture had been converted into rod-shaped crystals and the colorof the slurry had changed from light yellow to white. Refluxing of themixture was continued until the total reflux time was about five andthree-quarters hours. The mixture was then filtered while hot (about90°-95° C) and the white solid thus collected was washed with hot (about80° C) water until the washings were neutral to Brilliant Yellowindicator and colorless. The product was dried at 70° C. There was thusobtained 8.4 g of white rod-shaped crystals of disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate.X-ray diffraction data for this product correspond to the data givenabove for hydrated rod form A.

EXAMPLE 7

Disodium4,4'-bis(4,6-dichloro-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate wasprepared by interaction of 500 pounds of4,4'-diamino-2,2'-stilbenedisulfonic acid with a solution of 500 poundsof cyanuric chloride in 2100 pounds of acetone in an aqueous reactionmedium at pH 7-8 prepared by mixing 3200 pounds of crushed ice andapproximately 2100 pounds of 10 percent aqueous sodium hydroxidesolution. The disodium4,4'-bis(4,6-dichloro-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate thusobtained was mixed with 270 pounds of disodium phosphate and interactedat 15°-50° C with 625 pounds of aniline for thirty minutes and then thepH of the reaction mixture was adjusted to 6.7-6.8 by addingapproximately 600 pounds of 10 percent aqueous sodium hydroxide solutionduring a period of one hour.

The yellow amorphous disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateobtained as described above contained approximately 2.6 percent ofsodium chloride and 1.3 percent of disodium phosphate. To a 10 percentaqueous slurry of this product remaining after distilling offsubstantially all of the acetone in a 1800 gallon stainless steelpressure kettle there was added 125 pounds of aniline. The pH of theresulting mixture was adjusted to 10.5 by addition of approximately 200pounds of 50 percent aqueous sodium hydroxide solution. The mixture wasstirred at 85° C for thirty minutes with the kettle open, and then afterchecking to assure that the pH was still 10.5 the kettle was closed. Themixture was heated at 125° C for four hours and was then cooled to 100°C. The kettle was vented, and the mixture (which had a pH of 10.3) waspumped into a filter press. The crude product was washed in the presswith a hot (95°-100°C) solvent prepared by mixing 800 gallons of water,50 pounds of sodium chloride, and 12 pounds of 50 percent aqueous sodiumhydroxide solution. The presscake obtained in this manner was washedwith a cold solution of 100 pounds of sodium chloride in 800 gallons ofwater and was then dried. There was thus obtained 1250 pounds ofdisodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate inthe form of white crystalline rods.

By purification of the amorphous disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateused as a starting material in the foregoing method, so that theinorganic salts are removed, the heating period in the autoclave can bereduced to about twenty minutes for substantially complete conversion ofthe amorphous form to the crystalline rod form. X-ray diffraction datafor this product correspond to the data given above for thesubstantially anhydrous rod form A.

EXAMPLE 8

A slurry of approximately 60 g of yellow amorphous disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate (asan unpurified water-wet pulp obtained by interacting aniline withdisodium4,4'-bis(4,6-dichloro-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate andcontaining one molecular equivalent excess of aniline for each molecularequivalent of product) was heated for four hours at 155° C with stirringin a stainless steel autoclave. The resulting product, consisting ofwhite rod-shaped crystals, was isolated by filtration and was washedwith 500 ml of an aqueous solution containing approximately 0.5 percentsodium chloride.

X-ray diffraction data for the product obtained according to thisprocess corresponded to the data given above for rod form B. Moreover,visual examination, index of refraction values, and X-ray diffractiondata showed that the product prepared as described above was from 80 to100 percent, and probably more than 90 percent in the form ofcrystalline rod form B.

EXAMPLE 9

A detergent composition containing the crystalline needle form ofdisodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatewas prepared as follows. A 100 mg portion of the crystalline needle formwas placed in a mortar, 1 ml of 10 percent aqueous sodium chloridesolution was added, and the mixture was ground gently for a few secondsto produce a uniform dispersion. There was then added, each in smallportions, 20 ml of distilled water and 20 g of a white solid detergent(which consisted of 21.8 percent of a mixture of sodium lauryl sulfateand sodium dodecylbenzenesulfonate, 18.2 percent of sodium sulfate, and60.0 percent of trisodium phosphate, and which contained no opticalbleaching agent) and the resulting mixture was ground until a smoothpaste was obtained. This paste was placed in a Petri dish and driedovernight at 80°-90° C. The dry product was ground and passed through20-mesh and 60-mesh sieves. The solid which passed through the 20-meshsieve but not through the 60-mesh sieve was retained for testing.

Soap compositions are prepared as above by substituting a soap powderfor the detergent employed therein.

The detergent composition described in Example 6 (called herein SampleI) and a detergent composition identical to the one described in Example6 except that the amorphous form of4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatewas used in place of the crystalline needle form (called herein SampleII) were examined under simulated daylight (using a Macbeth lampcombining incandescent, fluorescent, and ultraviolet lights) andevaluated as to color in comparison with the untreated solid whitedetergent on the basis of the following scale (which is an arbitrarygrading and which validly compares the relative color grades of thesamples):

    ______________________________________                                        Color Grade          Definition                                               ______________________________________                                        +2          Strong brightening effect                                         +1          Good brightening effect                                            0          Color of the untreated white                                                  solid detergent                                                   -1          Barely descernible discoloration                                              (ordinarily, a yellowing effect)                                  -2          Objectionable discoloration or                                                a slight tint                                                     -3          Discoloration stronger than a                                                 tint                                                              -4          Any discoloration stronger than                                               the Color Grade designated -3                                     ______________________________________                                    

The results of this grading of the sample compositions were as follows:

    ______________________________________                                                Sample I,   Color Grade of +2                                                 Sample II,  Color Grade of -2                                         ______________________________________                                                -

Further portions of the detergent compositions Samples I and II preparedas above described were used to launder white cotton swatches at a bathtemperature of 49° C for twenty minutes. After completion of theapplication of the respective test samples to the cotton swatches, eachswatch of treated cloth was compared visually and with a Lumetroncolorimeter. The results thus obtained showed that Samples I and II eachproduced a satisfactory whitening and brightening effect on the whitecotton swatches.

The laundering treatment was repeated with each of Samples I and II inthe above-described manner with the modification that sufficient 5percent aqueous sodium hypochlorite solution was added to produce aconcentration of 0.02 percent of sodium hypochlorite in the wash liquidand after two minutes of the wash cycle one-half the hypochlorite wasneutralized with an aqueous sodium sulfite solution. After four minutes,the balance of the hypochlorite solution was neutralized with sodiumsulfite and the twenty-minute wash cycle was then completed. As comparedwith the corresponding test swatches obtained above when no hypochloritewas used, the test swatch washed with Sample I in the presence ofhypochlorite showed approximately 47 percent less whitening andbrightening effect and the test swatches washed with Sample II showedapproximately 60 percent less whitening and brightening effect.

When the crystalline needle form and the amorphous form of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatewere each dissolved in water prior to use, so as to destroy theirdistinguishing characteristics of physical form, the respectiveresulting solutions gave essentially identical results as whitening andbrightening agents in laundering tests in the presence of sodiumhypochlorite as well as in the absence of sodium hypochlorite.

Preparations of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatewherein the percentage of crystalline needle form was graduallyincreased gave progressively better test results until the optimumresults obtained with the substantially pure crystalline needle formwere attained. Thus, for instance, the Color Grade values for whitedetergent compositions having incorporated therein by the proceduredescribed above 0.5 percent of disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatehaving the indicated percentages of crystalline needle form andamorphous form were as follows:

    ______________________________________                                        Composition of Test Sample                                                    Crystalline Needles                                                                            Amorphous                                                    (Percent)        (Percent)   Color Grade                                      ______________________________________                                        100              --          +2                                               90               10          +1.8                                             80               20          +1.7                                             70               30          +1.3                                             --               100         -2                                               ______________________________________                                    

In addition to visual grading, these samples were measured on a Huntercolor and color difference meter, Hunterlab Model D25, HunterLaboratories. As can be seen, to enjoy in practical degree theadvantageous properties of the new crystalline needle form, thepercentage of the crystalline needle form in the disodium4,4'-bis(4-anilino-6-morpholino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate should be atleast about 80 percent, and is preferably 95-100 percent.

EXAMPLE 10

A detergent composition containing the novel crystalline needle form ofdisodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatedescribed in Example 7 was prepared as follows:

An accurately weighed sample of 62 mg. of the novel crystalline needleform of the compound was placed in a mixing tube along with one ml of0.1N aqueous sodium hydroxide solution. The mixture was triturated for30 seconds with a motor-driven pestle. Twenty grams of the solid whitedetergent (which consisted of 21.8 percent of a mixture of sodium laurylsulfate and sodium dodecylbenzenesulfonate, 18.2 percent of sodiumsulfate, and 60.0 percent of trisodium phosphate, and which contained nooptical bleach) and 20 ml of water were then added and the mixture wastriturated again until a smooth paste was obtained. The mixture was thenplaced in a Petri dish and dried overnight at 90°-100° C. The cake wasbroken up with a spatula, and the chunks were forced through a 20-meshsieve. The screened material was collected on a 60-mesh sieve and shakento remove the fines. The brightener-detergent composition retained onthe 60-mesh screen was used for testing.

In the foregoing manner three detergent compositions were preparedcontaining, respectively, the crystalline rod form of disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate(Sample III), the crystalline plate form of the compound (Sample IV),and the amorphous form of the compound (Sample V).

The detergent composition Samples III, IV and V were examined undersimulated daylight (using a Macbeth lamp combining incandescent,fluorescent, and ultraviolet lights) and evaluated as to color incomparison with the untreated solid white detergent on the basis of thescale described in Example 9. The results of this grading of the samplecompositions were as follows:

    ______________________________________                                                Sample III, Color Grade of +1                                                 Sample IV,  Color Grade of -2                                                 Sample V,   Color Grade of -3                                         ______________________________________                                                -

When the above tests were repeated using various grades of commerciallyavailable disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate inthe amorphous and crystalline plate forms, the Color Grade valuesobtained were consistently -2 and -3. On the other hand, when tested inthe same manner, various batches of the novel crystalline rod formsherein described consistently gave values of at least 0; usually therewas obtained a value of +1, and occasionally +2.

Further portions of the detergent compositions Samples III, IV and Vprepared as above described were used to launder white cotton swatchesin a stainless steel cylindrical specimen container in a Launder-O-Meter(a standard laboratory washing machine of the American Association ofTextile Chemists and Colorists described in the Technical Manual andYear Book of the Association, Howes Publishing Co., Inc., New York,N.Y., Volume XXVIII, 1952, pages 82-83) at a bath temperature of 40° Cfor twenty minutes. After completion of the application of therespective test samples to the cotton swatches, each swatch of treatedcloth was compared visually. The results thus obtained showed thatSamples III, IV and V each produced a satisfactory whitening andbrightening effect on the white cotton swatches.

The laundering treatment was repeated with each of Samples III, IV and Vin the above-described manner with the modification that sufficient 5percent sodium hypochlorite solution was added to produce aconcentration of 0.01 percent of sodium hypochlorite in the wash liquidand after 2 minutes of the wash cycle the hypochlorite was neutralizedwith an aqueous sodium hydrosulfite solution, and the 20-minute washcycle was then completed. As compared with the corresponding testswatches obtained above when no hypochlorite was used, the test swatchwashed with Sample III in the presence of hypochlorite showedapproximately 5 to 10 percent less whitening and brightening effect andthe test swatches washed with Samples IV and V respectively showed ineach instance approximately 75-80 percent less whitening and brighteningeffect.

When the crystalline rod, crystalline plate, and amorphous forms ofdisodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatewere each dissolved in water prior to use, so as to destroy theirdistinguishing characteristics of physical form, the respectiveresulting solutions gave essentially identical results as whitening andbrightening agents in laundering tests in the presence of sodiumhypochlorite as well as in the absence of sodium hypochlorite.

Preparations of mixtures of the amorphous form and the rod forms ofdisodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatewherein the percentage of crystalline rod form was gradually increasedgave progressively better test results until the optimum resultsobtained with the substantially pure crystalline rod form were attained.Thus, for instance, the Color Grade values for white detergentcompositions having incorporated therein by the procedure describedabove 0.3 percent of disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatehaving the indicated percentages of crystalline rod form and amorphousform were as follows:

    ______________________________________                                        Composition of Test Sample                                                    Crystalline Rods                                                                             Amorphous                                                      (Percent)      (Percent)   Color Grade                                        ______________________________________                                        100            --          +1                                                 90             10           0                                                 80             20          -1                                                 70             30          -2                                                 --             100         -3                                                 ______________________________________                                    

As can be seen, to enjoy in practical degree the advantageous propertiesof the new crystalline rod forms, the percentage of the crystalline rodforms in the disodium4,4-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonateshould be at least about 80 percent, and is preferably 90-100 percent.

The fact that the above-noted beneficial effects of crystalline rodformation of disodium4,4'-bis(4,6-dianilino-s-triazin-2ylamino)-2,2'-stilbenedisulfonate arenot ascribable to mere purification of the amorphous product wasdemonstrated by the following procedures: 200 parts of disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate inthe form of crystalline rod form B were refluxed in 800 parts of 60percent aqueous acetone, containing sufficient sodium hydroxide to givea basic reaction to phenolphthalein, until the product was completelydissolved. Hydrochloric acid was then added until the pH of the mixturewas 7.0, and the solvent was removed by distillation until the pottemperature was 73° C. At this point the pH of the mixture was 6.3. Theprecipitated product was removed by filtration and washed with 2 percentsodium chloride solution. The filter cake was reslurried in 2000 partsof 2 percent chloride solution at room temperature and filtered andwashed as before. The dried product was yellow and amorphous, asdetermined by visual examination under a microscope.

Eleven and one-tenth parts of the above yellow amorphous form ofdisodium4,4-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate wassuspended in 150 parts of water containing sufficient sodium hydroxideto bring the pH of the mixture to 11.0. The mixture was heated to98°-99° C and aniline was added in small portions until the mixturecontained a total of five parts of aniline. After approximately onehour, the suspension returned to a white color. The small crystals whichhad formed were found to have the crystalline structure of rod form A.

Another portion of 22.3 parts of the yellow amorphous form of disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2-stilbenedisulfonatedescribed above was slurried in 220 parts of water containing sodiumhydroxide slightly greater than pH 11. Three and one-tenth parts ofaniline, 2 parts of sodium chloride and 1 part of 20 percent aqueousnonylphenylpolyethylene glycol ether surface active agent were thenadded. The mixture was washed into an autoclave with 133 parts of waterand heated at 150° C for 2 hours. An additional 1.5 parts of anilinewere added, and the autoclaving was continued at 150° C for one hour.The white crystalline product which had formed was filtered and washedwith 400 ml of 1 percent sodium chloride solution. When dried, theproduct was found to have the crystalline structure of rod form B.

Thus, rod form B was converted to the undesirable amorphous form, andthe amorphous form reconverted both to rod form A and rod form B. In theamorphous form, prepared by simple precipitation of a solution ofdissolved rod form B crystals, the characteristic undesirable properties(i.e., poor Color Grade and bleach resistance) had returned, thusdemonstrating that those properties were not ascribable to impurities.Accordingly, regardless of the manner in which the novel rod forms A andB are formed, the same results are obtained.

We claim:
 1. A detergent composition consisting essentially of adetergent and an effecitive brightening amount of the compound disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonate inthe form of birefringent crystalline rods in which the lowest index ofrefraction has a value between 1.53 and 1.54 and is parallel to the longaxis, said rods being characterized by the following X-ray diffractiondata:

    ______________________________________                                        INTERPLANAR SPACINGS, A                                                       6.23                                                                          5.90                                                                          5.70                                                                          5.59                                                                          5.51                                                                          5.34                                                                          4.90                                                                          4.85                                                                          4.60                                                                          3.98                                                                          3.82                                                                          3.64                                                                          3.44                                                                          3.28                                                                          3.22                                                                          ______________________________________                                    


2. A detergent composition consisting essentially of a detergent and aneffective brightening amount of a new article of manufacture which isthe compound disodium4,4'-bis(4,6-dianilino-s-triazin-2-ylamino)-2,2'-stilbenedisulfonatewherein approximately 80 to 100 percent of said compound is in the formof birefringent crystalline rods in which the lowest index of refractionhas a value between 1.53 and 1.54 and is parallel to the long axis, saidrods being characterized by the following X-ray diffraction data:

    ______________________________________                                        INTERPLANAR SPACINGS, A                                                       6.23                                                                          5.90                                                                          5.70                                                                          5.59                                                                          5.51                                                                          5.34                                                                          4.90                                                                          4.85                                                                          4.60                                                                          3.98                                                                          3.82                                                                          3.64                                                                          3.44                                                                          3.28                                                                          3.22                                                                          ______________________________________                                           S


3. A detergent composition consisting essentially of a detergent and aneffective brightening amount of a novel crystalline rod form of abis-triazinylaminostilbene of the formula ##STR3## which is prepared bysubjecting the amorphous or ordinary crystalline forms thereof to atemperature of at least 155° C in aqueous aniline medium atsuperatmospheric pressure in an autoclave for several hours to convertit to the novel crystalline form.